1,593 research outputs found
PDF-Malware Detection: A Survey and Taxonomy of Current Techniques
Portable Document Format, more commonly known as PDF, has become, in the last 20 years, a standard for document exchange and dissemination due its portable nature and widespread adoption. The flexibility and power of this format are not only leveraged by benign users, but from hackers as well who have been working to exploit various types of vulnerabilities, overcome security restrictions, and then transform the PDF format in one among the leading malicious code spread vectors. Analyzing the content of malicious PDF files to extract the main features that characterize the malware identity and behavior, is a fundamental task for modern threat intelligence platforms that need to learn how to automatically identify new attacks. This paper surveys existing state of the art about systems for the detection of malicious PDF files and organizes them in a taxonomy that separately considers the used approaches and the data analyzed to detect the presence of malicious code. © Springer International Publishing AG, part of Springer Nature 2018
Big Data in Critical Infrastructures Security Monitoring: Challenges and Opportunities
Critical Infrastructures (CIs), such as smart power grids, transport systems,
and financial infrastructures, are more and more vulnerable to cyber threats,
due to the adoption of commodity computing facilities. Despite the use of
several monitoring tools, recent attacks have proven that current defensive
mechanisms for CIs are not effective enough against most advanced threats. In
this paper we explore the idea of a framework leveraging multiple data sources
to improve protection capabilities of CIs. Challenges and opportunities are
discussed along three main research directions: i) use of distinct and
heterogeneous data sources, ii) monitoring with adaptive granularity, and iii)
attack modeling and runtime combination of multiple data analysis techniques.Comment: EDCC-2014, BIG4CIP-201
The c-terminal extension of a hybrid immunoglobulin A/G heavy chain is responsible for its Golgi-mediated sorting to the vacuole
We have assessed the ability of the plant secretory pathway to handle the expression of complex heterologous proteins by investigating the fate of a hybrid immunoglobulin A/G in tobacco cells. Although plant cells can express large amounts of the antibody, a relevant proportion is normally lost to vacuolar sorting and degradation. Here we show that the synthesis of high amounts of IgA/G does not impose stress on the plant secretory pathway. Plant cells can assemble antibody chains with high efficiency and vacuolar transport occurs only after the assembled immunoglobulins have traveled through the Golgi complex. We prove that vacuolar delivery of IgA/G depends on the presence of a cryptic sorting signal in the tailpiece of the IgA/G heavy chain. We also show that unassembled light chains are efficiently secreted as monomers by the plant secretory pathway
Coarse grained and fine dynamics in trapped ion Raman schemes
A novel result concerning Raman coupling schemes in the context of trapped
ions is obtained. By means of an operator perturbative approach, it is shown
that the complete time evolution of these systems (in the interaction picture)
can be expressed, with a high degree of accuracy, as the product of two unitary
evolutions. The first one describes the time evolution related to an effective
coarse grained dynamics. The second is a suitable correction restoring the {\em
fine} dynamics suppressed by the coarse graining performed to adiabatically
eliminate the nonresonantly coupled atomic level.Comment: 12 pages, no figure
PBFT vs proof-of-authority: Applying the CAP theorem to permissioned blockchain
Permissioned blockchains are arising as a solution to federate companies prompting accountable interactions. A variety of consensus algorithms for such blockchains have been proposed, each of which has different benefits and drawbacks. Proof-of-Authority (PoA) is a new family of Byzantine fault-tolerant (BFT) consensus algorithms largely used in practice to ensure better performance than traditional Practical Byzantine Fault Tolerance (PBFT). However, the lack of adequate analysis of PoA hinders any cautious evaluation of their effectiveness in real-world permissioned blockchains deployed over the Internet, hence on an eventually synchronous network experimenting Byzantine nodes. In this paper, we analyse two of the main PoA algorithms, named Aura and Clique, both in terms of provided guarantees and performances. First, we derive their functioning including how messages are exchanged, then we weight, by relying on the CAP theorem, consistency, availability and partition tolerance guarantees. We also report a qualitative latency analysis based on message rounds. The analysis advocates that PoA for permissioned blockchains, deployed over the Internet with Byzantine nodes, do not provide adequate consistency guarantees for scenarios where data integrity is essential. We claim that PBFT can fit better such scenarios, despite a limited loss in terms of performance
Generalized adhesion maps for predicting thin film transitions
Abstract Ž . Thin film transition TFT phenomena are of special interest to the petroleum industry. After crude-oil is trapped in reservoir rocks, it can alter the wettability of the rock surface, with profound implications for the subsequent transport of fluids. Correlation between the TFT and wettability alteration is qualitatively evident from many experiments. It is not clear, however, whether the TFT is a sufficient condition for wettability alteration. In this work we describe a generalized adhesion map, which locates the TFT in parameter space. Comparison of these maps with laboratory studies indicates that wettability alteration involves other mechanisms in addition to the TFT.
A new perturbative expansion of the time evolution operator associated with a quantum system
A novel expansion of the evolution operator associated with a -- in general,
time-dependent -- perturbed quantum Hamiltonian is presented. It is shown that
it has a wide range of possible realizations that can be fitted according to
computational convenience or to satisfy specific requirements. As a remarkable
example, the quantum Hamiltonian describing a laser-driven trapped ion is
studied in detail.Comment: 32 pages; modified version with examples of my previous paper
quant-ph/0404056; to appear on the J. of Optics B: Quantum and Semiclassical
Optics, Special Issue on 'Optics and Squeeze Transformations after Einstein
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